名詞 eight:

1. the cardinal number that is the sum of seven and one
   同義詞：8, VIII, eighter, eighter from Decatur, octad, ogdoad, octonary, octet
2. a group of United States painters founded in 1907 and noted for their realistic depictions of sordid aspects of city life
   同義詞：Ashcan School

形容詞 eight:

1. being one more than seven
   同義詞：8, viii

1. I'm hardly functional if I don't get eight hours' sleep!
   我要是不睡上八個(gè)小時(shí)就無法工作。
2. You are restricted to eight liters of duty-free wine.
   攜帶的免稅酒不得超過八升。
3. There are eight forts in this section of the Great Wall.
   這一段長城有八個(gè)垛口。
4. Five members voted for the proposal, eight voted against, and two abstained.
   對于這項(xiàng)建議，五人投票贊成，八人反對，兩人棄權(quán)。
5. I am sorry, you can only buy traveler's check at Window Eight.
   對不起，你只能在八號(hào)窗口買旅行支票。
6. His eight sons largely inherited his fortune.
   他的八個(gè)兒子繼承了他的大部分遺產(chǎn)。
7. There are eight students in the classroom.
   教室里有八個(gè)學(xué)生。

eight

n.（名詞）
The cardinal number equal to 7 + .
八：等于7+的基數(shù)
The eighth in a set or sequence.
第八：一組或一列順序中的第八個(gè)
Something having eight parts, units, or members, especially:
八個(gè)一組：有八個(gè)部分或成員的東西，尤指：
Sports An eight-oared racing shell.
【體育運(yùn)動(dòng)】 八槳的劃船隊(duì)
An eight-cylinder engine or motor vehicle.
八汽缸發(fā)動(dòng)機(jī)或八汽缸汽車

來源：
Middle English eighte
中古英語 eighte
from Old English eahta * see oktô(u)
源自 古英語 eahta *參見 oktô(u)

【引伸】
eight
adj.（形容詞）
pron.（代詞）